Video calling and videoconferencing systems are an example of types of system that capture a stereoscopic pair of images (which may be referred to as a “stereo image”) of a head. Such systems generally capture head images of source and destination observers. The source observer's head image is captured by a source camera and the source observer views an image on a source display of the destination observer's head. The destination observer's head image is captured by a destination camera and the destination observer views an image on a destination display of the source observer's head.
In natural face to face communication, it is strongly desirable for the source and destination observers to interact with correct gaze cues. In correct gaze interaction, the camera for the source observer appears to be co-located in the eye region of destination observer image and vice versa.
In a known arrangement, a camera and beam combiner such as a half silvered mirror may be positioned in front of the source display. The camera output aperture may be imaged by the beam combiner to be co-located in a region close to the destination observer eye image. The destination observer perceives an image of the source observer's eyes that was recorded from a location that is optically in proximity with the location of the destination observer's eyes. Such an arrangement can achieve natural gaze correction; however, is bulky and impractical for flat panel displays, particularly for mobile displays.
By comparison, in known 2D video calling mobile display systems, the source camera aperture location is positioned outside the active area of the display and is thus separated from the destination observer eye image locations and is not co-located in the region around the source observer's eyes.
The destination observer sees the source observer not appearing to look into their eyes when the source observer is looking at the eyes of the image of the destination observer.
In a stereoscopic video calling system, two cameras are placed outside the display active area. Viewed individually as 2D images, each of the stereoscopic pair of images has incorrect gaze as the cameras are not co-located in the area of the destination observer eye images.